stunnel: Home

AboutCurrent FeaturesPlanned FeaturesScreenshotOperating SystemsPort MaintainersDocumentationExamplesDownloadsSupportCNG InterfacesContact

Stunnel is a proxy designed to add TLS encryption functionality to existing clients and servers without any changes in the programs' code.
Its architecture is optimized for security, portability, and scalability (including load-balancing), making it suitable for large deployments.
Stunnel uses the OpenSSL library for cryptography, so it supports whatever cryptographic algorithms are compiled into the library. It can benefit from the FIPS 140-2 validation of the OpenSSL FIPS Provider, as long as the building process meets the OpenSSL FIPS 140-2 Security Policy. Our latest Windows installer includes the OpenSSL FIPS Provider.
Stunnel is a free software authored by Michał Trojnara. Although distributed under GNU GPL version 2 or later with OpenSSL exception, stunnel is not a community project. We retain the copyright of the source code. Please contact us for commercial support or non-GPL licenses. Free, community-based support is also available via stunnel-users mailing list.

We offer commercial support with several levels of response time up to 24/7/365 helpline.

Support

Download latest version of stunnel and try it out yourself.

Downloads

Excel Easy: #1 Excel tutorial on the net
Academized.com thesis writing service

Stunnel presents itself as a dedicated TLS encryption proxy designed to seamlessly integrate into existing client and server applications, effectively adding cryptographic protection without demanding modifications to the underlying software code. The core architectural design prioritizes security, ensuring operational portability, and the capacity for scaled deployments, including the possibility of load balancing. A fundamental aspect of Stunnel’s functionality relies on the utilization of the OpenSSL library for cryptographic operations. This strategic choice guarantees compatibility with any cryptographic algorithms compiled into the OpenSSL library, affording users the potential to leverage the validation processes established by the FIPS 140-2 security standard, provided the building process adheres to the requisite OpenSSL FIPS 140-2 Security Policy. Notably, the most recent release of Stunnel incorporates the OpenSSL FIPS Provider.

Michał Trojnara authored this software, and it is distributed under the terms of the GNU General Public License version 2 or later, with an OpenSSL exception. It’s crucial to acknowledge that, despite this licensing framework, Stunnel is not considered a community-driven project; the original author retains ownership of the source code. As a consequence, prospective users seeking commercial support or licenses outside the scope of the GNU GPL, are directed to contact the developer directly. While free, community-based support is available through the “stunnel-users” mailing list.

The vendor offers tiered commercial support options, ranging from standard response times to a 24/7/365 helpline, reflecting a commitment to robust operational assistance for organizations deploying Stunnel. Prospective users are encouraged to experiment with the latest version of Stunnel directly through the provided download mechanisms.